(1. 中南大学材料科学与工程学院，长沙 410083；
2. 中南大学材料科学与工程学院有色金属材料科学与工程教育部重点实验室，长沙 410083)
摘 要: 通过光学显微镜(OM)及电子背散射衍射分析技术(EBSD)研究室温多向锻压(MDF)下AZ31镁合金在473 K下的静态再结晶(SRX)行为，对高密度孪晶组织的再结晶行为、显微组织演变、再结晶动力学及退火初期再结晶晶粒取向进行研究。结果表明：室温多向锻压AZ31镁合金的累积应变量越大，孪晶密度越高，退火过程中越容易发生再结晶。不管试样累积应变量高还是低，硬度曲线在退火过程中均分为3个阶段，且第一阶段硬度值均基本不变，但低累积应变量试样比高累积应变量试样更迟进入第二阶段，进入第三阶段低累积应变量试样硬度继续呈下降趋势而高累积应变量试样硬度基本处于稳态。高累积应变量试样能用JMAK方程很好地描述退火组织的再结晶过程，但低累积应变量试样却不能。退火初期，再结晶晶粒与母相仍然保持孪晶关系，且其基面取向与最终压缩方向垂直或平行。
关键字: AZ31镁合金；孪晶；静态再结晶；再结晶动力学；晶粒取向
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Materials Science and Engineering,
Ministry of Education, Central South University, Changsha 410083, China）
Abstract:Static recrystallization (SRX) behavior of a wrought AZ31 magnesium alloy at 473 K was studied after multi-directional forging (MDF) using optical microscopy (OM) and electron backscattering microscopy (EBSD). Effects of introduced high-density twins on SRX behavior, microstructural development, SRX kinetics and initial orientation of SRX grains during the isothermal annealing were investigated. The results show that SRX can be accelerated through high-density twins introduced by high cumulative strain. The variation of hardness (HV) with annealing time of wrought samples includes three periods irrespective of prior strain: HV hardly changes in the early stage of annealing and drops rapidly in the middle stage until it finally approaches the fully annealed value. At high cumulative strain, variation of HV proceeds earlier into the middle stage and then reaches a steady value while HV keeps dropping gradually in the final stage at low cumulative strain. The relationship between recrystallization volume fraction and annealing time can be perfectly described by JMAK equation at high cumulative strain but cannot at low cumulative strain. SRX grains exhibit almost same orientations of prior twins with its basal plane aligned parallel and perpendicular to the forging direction of the last pass.
Key words: AZ31 magnesium alloy; twin; static recrystallization; recrystallization kinetics; grain orientation
